Nuclear magnetic resonance (NMR) is a physical phenomenon involving quantum mechanical magnetic properties of atomic nuclei in the presence of an applied, external magnetic field. NMR phenomena can be observed with an NMR spectrometer and used to study molecular physics, crystalline and non-crystalline materials in a process called NMR spectroscopy.
To perform a static nuclear magnetic resonance experiment, a liquid or solid sample is typically placed in a glass tube that can be inserted into the bore of a magnet. In addition to static measurements, NMR spectroscopy can also be used to measure kinetic chemical reactions using stopped flow or continuous flow methods. In these methods, a reaction takes place in a reaction vessel that is external to the magnetic field and the reactants and products from the reaction are pumped through a continuous flow, or flowthrough, cell located in the magnetic field. This cell includes the glass tube and a structure that mimics the rotor structure used in static studies, but includes inlet and outlet transport capillary tubes in order to introduce the materials from the reaction vessel into the cell and return the materials to the reaction vessel after the measurement has been made.
Most applications of flow NMR use flow probes that are dedicated to measurements of single nucleus or group of nuclei in order to optimize the sample volume, sensitivity and resolution. Accordingly, these dedicated probes are expensive, relatively inflexible and generally have a limited temperature range.